diff --git a/UnifiedFlashingPlatformTransport.cs b/UnifiedFlashingPlatformTransport.cs
index 52407ae..e4c0fc3 100644
--- a/UnifiedFlashingPlatformTransport.cs
+++ b/UnifiedFlashingPlatformTransport.cs
@@ -60,6 +60,51 @@ namespace UnifiedFlashingPlatform
             }
         }
 
+        //
+        // Not valid commands
+        //
+        /* NOK    */ private static string Signature = "NOK";
+        /* NOKX   */ private static string ExtendedMessageSignature = Signature + "X";
+        /* NOKXC  */ private static string CommonExtendedMessageSignature = ExtendedMessageSignature + "C";
+        /* NOKXF  */ private static string UFPExtendedMessageSignature = ExtendedMessageSignature + "F";
+
+        //
+        // Normal commands
+        //
+        /* NOKF   */ private static string FlashSignature = Signature + "F";
+        /* NOKI   */ private static string HelloSignature = Signature + "I";
+        /* NOKM   */ private static string MassStorageSignature = Signature + "M";
+        /* NOKN   */ private static string TelemetryEndSignature = Signature + "N";
+        /* NOKR   */ private static string RebootSignature = Signature + "R";
+        /* NOKS   */ private static string TelemetryStartSignature = Signature + "S";
+        /* NOKT   */ private static string GetGPTSignature = Signature + "T";
+        /* NOKV   */ private static string InfoQuerySignature = Signature + "V";
+        /* NOKZ   */ private static string ShutdownSignature = Signature + "Z";
+
+        //
+        // Common extended commands
+        //
+        /* NOKXCB */ private static string SwitchModeSignature = CommonExtendedMessageSignature + "B";
+        /* NOKXCC */ private static string ClearScreenSignature = CommonExtendedMessageSignature + "C";
+        /* NOKXCD */ private static string GetDirectoryEntriesSignature = CommonExtendedMessageSignature + "D";
+        /* NOKXCE */ private static string EchoSignature = CommonExtendedMessageSignature + "E";
+        /* NOKXCF */ private static string GetFileSignature = CommonExtendedMessageSignature + "F";
+        /* NOKXCM */ private static string DisplayCustomMessageSignature = CommonExtendedMessageSignature + "M";
+        /* NOKXCP */ private static string PutFileSignature = CommonExtendedMessageSignature + "P";
+        /* NOKXCT */ private static string BenchmarkTestsSignature = CommonExtendedMessageSignature + "T";
+
+        //
+        // UFP extended commands
+        //
+        /* NOKXFF */ private static string AsyncFlashModeSignature = UFPExtendedMessageSignature + "F";
+        /* NOKXFI */ private static string UnlockSignature = UFPExtendedMessageSignature + "I";
+        /* NOKXFO */ private static string RelockSignature = UFPExtendedMessageSignature + "O";
+        /* NOKXFR */ private static string ReadParamSignature = UFPExtendedMessageSignature + "R";
+        /* NOKXFS */ private static string SecureFlashSignature = UFPExtendedMessageSignature + "S";
+        /* NOKXFT */ private static string TelemetryReadSignature = UFPExtendedMessageSignature + "T";
+        /* NOKXFW */ private static string WriteParamSignature = UFPExtendedMessageSignature + "W";
+        /* NOKXFX */ private static string GetLogsSignature = UFPExtendedMessageSignature + "X";
+
         public byte[] ExecuteRawMethod(byte[] RawMethod)
         {
             return ExecuteRawMethod(RawMethod, RawMethod.Length);